Ophthal dynameter



Patented Apr. I8, 1899.

c. msnowfl. OPHTHAL DYNAMETER.

(Application filed Dec- 18, 1897.)

(No Model.)

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UNITED STATES PATENT Orrice.

CHRISTIAN H. BROXVN, OF PHILADELPHIA, PENNSYLVANIA.

OPHTHA'L DYNAMETER.

SPECIFICATION forming part of Letters Patent N0. 623,131, dated April 18, 1899.

Application filed December 18, 1897. Serial No. 662,398. (No model.)-

To all whom it may concern.-

Be it known that I, CHRISTIAN H. BROWN, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Ophthai Dynameters, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention has for its object to provide an ophthal dynameter for use in ophthalmic tests, as more fully set forth hereinafter.

In the accompanying drawings, Figure 1 is a perspective view of an apparatus constructed in accordance with my invention. .Fig. 2 is a perspective view of a portion of the opposite side of the indicating-scale of the apparatus. Figs. 3 and a are detached perspective views of test-objects which may be used. Figs. 5 and 6 are sectional elevations of portions of the apparatus. Fig. 7 is a transverse sec tional elevation of'aportion of the apparatus on the line 7 7, Fig. 6; and 'Fig. 8 is a sectional plan view on the line 8 8, Fig. 5.

The apparatus is designed for comparative tests of the amplitude of accommodation of vision in combination with an age-scale for indicating whether above or below the normal.

Referring to the drawings, A represents a tripod having a central hollow standard a, terminating at its upper end in a strengthening-ring 1), into which is tapped a thread for the reception of a set-screw B. The standard a is adapted to receive and support a vertically-adj ustable tube or bar 0, which is held in any vertical position desired by the turning of the set-screw B, it being noted that the upper portion of the standard a is slit to form a spring-tongue b, which is forced by the set-screw into contact with the bar or tube O.

Theupper end of the bar or tube O is flattened at c and receives and supports a tubular bearing D, in which latter is supported the end of screw-shaft E, the outer end of which finds a bearing in a plate 6, and at a point outside the plate is secured a knob f, having a serrated or milled periphery for convenience in turning the screw-shaft.

Gr represents a fiat bar extending from the flattened portion 0 of the bar 0 to the plate 2 and having contracted threaded ends which pass through the portions 0 and e and serve not only to hold the bar in position, but to brace andin a measure su pport the screw-shaft E. On one side of this bar is marked a scale or scales in inches or centimeters, or both, as shown in Fig. 1, and on the opposite side of the bar, as shown in Fig. 2, is marked a graduated scale, indicating years and dioptrics.

On the threaded shaft E is placed a holder H in the form of a flat plate having a central' opening it and provided with spring-clips h to supportand hold a testobject, such as shown in Figs. 3 and 4, or a card or letter, as may be desired, and on a small plate e are clips 75 for a similar purpose.

The lower portion of the plate H extends down to and partly around the scale-beam G, being provided with a slot-for the reception of the beam and the two forks thus formed being in the nature of indicating-fingers Z. From the rear of the plate H extends a cylinder M, slotted longitudinally atm and adapted to receive a threaded nut N, arranged to be traveled by the turning of the screw-shaft. The nut is preferably provided with a central body of Babbitt or similar metal to prevent excessive friction and is held to its work by a coiled spring 02. The nut is prevented from turning bya small screw 92, extending through the slot m. At the end of the cylinder M is a closing-cap 19, held in place by small screws p, and the arrangement is such that on the turning of the screw-shaft by its knobfwill result in the travel of this cylinder and plate H back and forth along the screw and the scale G.

On the sleeve D is a block R, which may be moved back and forth on the sleeve and locked in any required position by a set-screw r. This block supports a plate R, of a width approximately equal to twice the distance between the eyes, and at its center is formed an opening r Immediately in the rear of the plate R the block R has a shoulder s for the support of a disk S, in which are formed two minute openings s, and said block is further provided with clips or supports t t, in which may be placed test-lenses if defective vision makes it necessary.

The width of plate R must be twice the distance between the eyes, so that no matter of the pupil of the eye under examination, so

that the rays passing through openings may enter the eye without being obstructed by the pupil.

1n using the apparatus the parts are arranged as shown in Fig. 1, with the plate S in position behind the opening T and one or the other of the test-objectsas, for instance, those shown in Figs. 3 and 4is placed in position on the movable plate H, after which said plate H may he traveled to and fro by the screw-shaft E to any distance required, or the plate H may be set with the indicators Z in a predetermined position or distance away from the plate R, governed by the age of the patient or otherwise, and when the test is applied it is readily determined whether or not the vision is above or below the normal standard either for distance or age or both.

The apparatus is exceedingly simple and convenient, is readily adjustable, and will instantl y show on either or both of itsscales the required data.

Having thus described my inveniion,what I claim, and desire to secure by Letters Patent, is

1. An ophthalmic measuring instrument comprising a plate of a width greater than twice the distance between the eyes of a person and having a central vision-opening, clips or supports at the rear of said plate for the reception of removable lenses, a holderfora test-object, and means for positively traveling said holder toward and from said plate, substantially as specified.

2. An ophthalmic measuring instrument comprising a plate of a width greater than twice the distance between the eyes of a person and having a central opening, a holder for a test-object, and means for regulating the distance between the plate and holder, substantially as specified.

3. An ophthalmic measuring instrument comprising a standard, a scale-bar secured thereto, a screw-shaft extending parallel to the scale-bar and indirectly supported thereby, a plate having a vision-opening, and a test-object holder mounted on the screw-shaft and having indicators or pointers adapted to travel along the scale-bar, substantially as specified.

4. In an ophthalmic measuring instrument a plate having a vision-opening, a scale-bar having thereon three independent scales indicating respectively age, distance, and diop tric measurements, a test-object holder having pointers adapted to travel over said bar, and means for adjusting the distance between the plate and the holder, substantially as specified.

5. The combination of the plate having a vision-opening, a holder for a test-object, a

stationary nut carried by said holder,-a screw shaft for traveling said nut, and a scale for determining the position of said holder.

6. The combination of the plate having a vision-opening, a test-object holder comprising a vertical plate having lower depending indicating-fingers, a scaleover which said fingers travel, a screw-shaft, means for turning the same, and a nut carried by the holder adapted to be engaged by said screw-shaft.

7. The combination of the holder, a cylinder M secured thereto, a nut in said cylinder,

a coiled spring acting on said nut, and a screw engaging said nut, substantially as specified.

8-. The combination of the plate having an opening, a removable disk S, having minute Vision-openings 8', arranged in a horizontal plane at a distance from each other less than the width of the pupil of the eye, aholder for a test-object, and means for regulating the distance between the plate and the holder,

substantially as specified.

In testimony whereof I affix my signature in the presence of two witnesses.

t I CHRISTIAN I-I. BROXVN. Vitnesses:

WM. BERKHEISER, J. B. MonRY. 

